Knowing who is sitting on which seat of a vehicle may be very useful, for example, a seat in a vehicle may be automatically adjusted to a posture preferred by a user, an air conditioning device may be automatically adjusted to a setting preferred by a user, and so on. Nowadays, more and more people carry at least one mobile device with them, such as a cell phone, a pad, and the like. Therefore, localizing a mobile device in a vehicle may be useful.